The present invention relates to a coffee machine in general, and to an electric coffee machine in particular.
Still more specifically, the invention relates to an espresso coffee machine for brewing coffee from coffee pods.
Coffee machines are already known which brew coffee from coffee pods by passing hot water through a coffee-containing pod located in a brewing or extraction chamber. Such machines are valued for the reliable reproducibility of their brewing results.
It is also known that there are coffee machines which supply cups of coffee of constant volume (and hence strength) and others which, on demand, supply cups of coffee of different volumes (and hence strengths) by varying the quantity of water which is made to pass through a coffee pod, or by using filters of different characteristics.
Let is be assumed, for purposes of the explanations hereafter, that the term "standard coffee" (i.e. coffee beverage of "standard" strength) refers to an espresso coffee beverage made by passing about 40 cc of hot water through a predetermined quantity of ground or powdered coffee beans in e.g. a pod. Let is further be assumed that the term "weak coffee" refers to an espresso coffee beverage made by passing a substantially higher quantity of hot water, about 120 cc, through an identical quantity of ground or powdered coffee beans. Of course, these quantities and the relationship between them are arbitrary and intended only to facilitate explanations.
The prior-art variable-volume coffee machines have several decided disadvantages. Chief among these are the fact that the beverage which results when the water volume is changed, will vary not only in quantity but also in taste and appearance (the creamy, foamy appearance of typical espresso), and also that brewing of a "weak" coffee requires a preparation time which is much longer (as much as 3-4 times longer) than the time required for preparation of the "standard" coffee.